1. Field of the Invention
Embodiments of the present invention generally relate to seismic survey design, and more particularly, to quality control of seismic data.
2. Description of the Related Art
Quality control of surface seismic data is typically measured using source seismic data and receiver seismic data. Source seismic data is typically provided by a seismic source, such as a vibrator. An example of source seismic data that may be used for quality control is a seismic source signal wavelet, which is the time signal measured at several points of the vibrator. The time signal is indicative of data quality and is directly affected by ground conditions, such as elastic properties, gradient and composition of the earth's surface. For example, boulders often cause point loading of the vibrator baseplate, thereby leading to poor signal being transmitted into the ground. Parameters used for quality control include force, total harmonic distortion, and elasticity and stiffness. A high force typically indicates a high distortion, and hence, a low quality of source signal. If a vibrator is operated in feedback mode, force typically increases on soft ground. Total harmonic distortion is indicative of the fidelity of the source signal. Elasticity and stiffness provide estimates of the elastic behavior of the ground below the vibrator baseplate and are therefore ideal calibration parameters for seismic data quality.
Quality control of seismic data at the seismic receivers is typically measured in a recording truck immediately after recording. Quality of seismic data at the receivers is often affected by non-linearity of the source signal and receiver coupling conditions. In soft ground, geophone coupling to the ground may lead to resonance and, therefore, high distortion of the seismic data. In addition, ambient noise from installations and natural sources, such as wind and water, may degrade data quality. Parameters used for quality control at the seismic receivers include noise, total harmonic distortion, offsets and drifts. Data quality of source and receiver signals generally depends on the properties at the location where the measurements are taken.
Current seismic technology, however, performs quality control on seismic data at the source and receivers only after acquisition of seismic data. Accordingly, a need exists in the art for performing quality control on seismic data prior to acquisition of seismic data to provide an opportunity to avoid or compensate for potential problem locations.